Restore volume of a VM which has been removed from a backup offering

[Pearl1594]

Description

This PR addresses https://shapeblue.atlassian.net/browse/FRO-3655 however, I see a possibility of regression wrt to usage - or MAYBE NOT because https://github.com/apache/cloudstack/blob/a5f55602fc3c21a56715c2b944f31c2b67f134ed/server/src/main/java/org/apache/cloudstack/backup/BackupManagerImpl.java#L1186 lists only VMs with non null backup offering IDs and that list of VMs in turn is sent to the syncBackupMetrics() method to generate an event

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• build/CI
• test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?

How did you try to break this feature and the system with this change?

[yadvr]

@Pearl1594 let's discuss, perhaps one solution could be that the backup itself stores information about the volumes?

[Pearl1594]

Yeah, that would be more ideal.